The present disclosure relates to self propelled power machinery. More particularly, the present disclosure relates to an apparatus for controlling speed range and braking in a power machine.
Power machines, such as skid steer or wheel loaders, can usually be found in many different construction sites. Loaders typically include a movable lift arm that can support a wide variety of interchangeable work tools such as a bucket or an auger. Most power machines also include a drive system that includes wheels or tracks for propelling the power machine.
The drive system is typically powered with an engine that operates a pair of hydraulic pumps that are each connected to hydraulic traction motors that, in turn, power movement of the wheels. Many power machines are equipped with speed range mechanisms that are capable of operating the power machine in one of a number of speed ranges, such as in high and low speed ranges. An operator can select the low speed range when traversing difficult terrain or operating a sensitive tool. The operator can also select a different speed range, such as a high speed range, when simply driving down a road.
It is desirable that under certain circumstances the power machine be positively stopped. Many power machines are equipped with a traction lock mechanism that stops the drive system from moving the wheels. The traction lock mechanism can be operated by the user, automatically, or both. One example of such a system is described in U.S. Pat. No. 5,551,523, which is incorporated by reference. There is a continuing need, however, to develop efficient and durable traction lock mechanism systems in power machines, including power machines having multiple speed ranges.